I Spatchcock my turkey, (and chickens too for that matter) when I smoke it. That's just the technical term for removing the backbone with a pair of kitchen sheers, then breaking the keel bone so it essentially lays flat.
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I then brine it using a number of different recipes. Then take;
2-3 whole onions quartered
2-3 stalks celery washed and broken into big pieces
3-4 carrots washed and broken into big pieces
1 bell pepper cut in big chunks
1 whole head of garlic unpeeled and cut in half across it's equator
A mixture of apples, oranges, lemons, most any firm-fleshed fruit washed, unpeeled and cut into big chunks
Several handfuls of the obvious FRESH herbs. Just wash them and leave them whole on the stems.
Make sure to add the backbone you cut out, and I cut the wingtips off at the first joint and add them as they have no real meat to speak of.
I take all this and pile it into a mound in a foil "hotel pan", usually a 1/2 pan will do as I do smaller turkeys when possible. Then form the bird over/around this mixture, cavity-side down, and season it liberally with whatever rub I'm interested in using, dissolved in about 3/4 to 1 whole stick of melted butter. Use enough rub, so that when you mix it in the butter, it comes out like loose, wet sand. Rub this ALL OVER THE BIRD, making sure to get the cavity, as well as UNDER THE SKIN, especially over the breast.
Add a combo of chicken stock, white wine and a few dashes of Worcester sauce, ONLY ENOUGH SO YOU CAN SEE IT IN THE PAN. Do NOT cover the veggie/herb mixture, and DO NOT have liquid up touching the bird.Tent the pan w/ foil, but do not seal the edges.
I heat my smoker w/ lump charcoal for about 45 mins to an hour, to a temp of 325, then add 2-3 logs of my wood. I like a combo of cherry and pecan, but use what you like. I let my wood burn down until it stops flaming, trying to keep the temp at no more than 325 when I put the bird on.
I cook it at this temp for about 1 hour, then uncover it and close the dampers to try and achive a temp of 275. I let that smoke for another hour to 1 1/2 hours, basting liberally every 20-30 mins, and pull it when the thigh and breast are about 160.
Cover tightly and let rest for at least 1 hour in a warm spot. Remove the bird and wrap it in foil. Drain the pan juices from the veggie-mix and discard (reserve the backbone). Defat them the drippings the best you can, and use this to make your gravy.
Holler if you have any ?'s, but there are some pretty good YouTube vids you can find that will probobly help you just as much.